Renewable fuse



L. W. ROSENTHAL AND G. J. LANG.

RENEWABLE FUSE.

APPLICATION FILED 956.24, 1918.

Patented May 17,1921.

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UNITED STATESv PATENT onirica.

LEON W. ROSENTHAL, F NEW YORK, N. Y., AND GUSTAVE J. LANG, OF WEEHAWKEN,

NEW JERSEY, ASSIGNORS T0 ARTHUR T. MURRAY, OF ALLENTUV, EENNSYL- VANIA.

RENEWABLE FUSE.

Patented May 17, 1921..

Application led December 24, 1918. Serial No. 268,134.

' vented certain new and useful Improvements in Renewable Fuses; and we do hereby declare the following to be a full, clear, and eX- act description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to renewable fuses of the kind which consists of a permanent fuse holder with terminals for connecting it in an electric circuit, and a renewable fuse adapted to be inclosed by the holder and electrically connected in a detachable manner to the terminals thereof. The object of the invention is e provide a permanent and comparatively cheap fuse holder which, when assembled, gives reliable and permanent contact between it and the terminals of the 'inclosed fuse, and at the same time permits rapid renewal of a blownout fuse without the use of special tools.

In the accompanying drawings illustrating several embodiments of the invention, Figure 1 is a section on line 1-1 of Fig. 2 of a knife blade type of fuse; Fig. 2 is a vside elevation thereof; Fig. 8 is a detail of one end of the tube Fig. 4 is a section on linel 4--4 of Fig. 1; Fig. 5 is a longitudinal section of a modified form of a knife blade type of fuse; F ig. 6 is a detail of one end thereof; Fig. 7 is a side elevation of a ferrule type of fuse; and Fig. 8 is a longitudinal section thereof. i

In all of the embodiments illustrated, the cylindrical tube 1 is open ended, and is made or formed of fiber, impregnated paper, or other suitable material. The renewable fuse 2 passes diagonally through the tube and has its end ortions folded over the ends of the tube to orm terminals 3 lying along the outer surface thereof at opposite sides. The caps 4 are of metal and have bayonet slots 5 for the side screws 6, so that the caps may be pulled off and forced on the tube without entirely withdrawin the screws. The fuse terminals have slots wide enough to pass over the heads of the screws, and one terminal projects at 8 beyond the end of the cap to show a capacity marking on the fuse.

The caps have openings at 9 for exhausting the gases. of combustion upon blow-out of a fuse, and these openings are covered by gauze 10 or other material suitable to prevent the entry of foreign matter into the tube.

In the knife blade types of fuses shown in Figs. 1 and, the knife hlades'll are riveted or otherwise suitably fastened to the caps to form the terminals of the fuse for insertion in the spring clips of a panel board. In 'the ferrule type of fuse shown in Fig. 7, the caps form the terminals of the fuse and may be inserted directly in spring fingers o the panel board.

In Figs. 1 to 4, the tube has a recess 12 nearaeach end for receiving a screw-threaded bearing plate 13, and a shallower recess 14 extending to the end of the tube for accommodating the fuse terminal. Flach plate, 13 1s of springy metal, as brass, of the size of the recess 12. When unstressed, it is substantially flat, but when strained upon forcing the cap in place and tightening the side screws 6, 1t conforms to the cylindrical surface of the tube and resilientl'y clamps the fuse terminals 3 between it and the cap to produce a permanent and durable contact between them. The recesses l2 and 14 are of such depth and configuration that neither the fuse terminals nor the bearing plates eX- tend above the outer surface of the tube, so that the caps fit closely around the tube.

In Figs. 5 and 6, each bearing plate 15 is fastened by a rivet 16 in a recess 17 extending to one end of the tube and being of sufficient depth throughout to. accomodate the plate andthe fuse terminal. In this case also, the bearing plates are fiat before assembly so as to resiliently clamp the fuse terminals between them and the caps.

The ferrule type of fuse shown in Figs. 7 and 8 is similar in its details of construction to the fuse of F' 1, excepting that the caps 18 are not provi ed withknife blades.

By reason of the recesses12 in the tubes of the fuses shown in Figs. 1 and 7, the bearfrom endwise displacement on the tube. However, in addition, the tubes may be perforated at 19 to permit the entry of the side screws. If desired, the erforations may be screw-threaded and t e bearing plates smoothly perforated,

To renew the fuse in any of the embodiments illustrated,vthe side screws 6 are loosened and the caps first turned circumferentially and then 'withdrawn in endwise direction, by reason of the bayonet slots 5. The fuse terminals are "then lifted from the screws, and the separated portions of the blown-out fuse removed from the tube. A. new fuse may then be extended through. the tube and folded over the bearing plates, whereupon the caps may be positioned and screwed down.

Having thus described our invention what we claim is: y

l. A renewable fuse consisting of an openended tube having recesses extending along the outer surface of the tube near the ends thereof, spring bearing plates located in the recesses and strained into substantial cony formity with the outer surface of the tube,

a fuse passing through the tube and folded over the plates Ato form fuse terminals, caps positioned' over the open ends of the tube and the fuse terminals, and means securing the caps against endwise displacement on the tube. y i

` 2. A. renewable fuse consisting of an open ended tube having recesses extending along the outer surface of the tube near the ends thereof, spring bearing plates located in the recesses and strained into substantial conformity with the outer surface of the tube, a fuse passing through the tube and folded over the plates to formfuse terminals, caps positioned over the open ends of the "tube and the fuse terminals, and side screws passing through the capsand the fuse terminals inte threaded engagement with the plates' to resiliently ,clamp the fuse terminals between the plates -and caps..

3. A renewable fuse consisting of an open ended tube having recesses extending along the outer surface of the tube near the ends thereof and also having perforations in said recesses, spring bearing plates located in the recesses and strained into substantial conformity with the outer surface of the tube, a fuse passing through the tube and folded over the plates to form fuse terminals, caps positioned over the open ends of the tube and the fuse terminals, and side screws passing through the caps and the fuse terminals into threaded engagement with the plates to resiliently clamp the fuse terminals between the plates and the caps, said screws passing into said perforations `to secure the caps against endwise displacement on the tube.

a. A renewable fuse consisting of an open.'

sitioned over the open ends of the tube and f the fuse terminals and having bayonet slots in registry with said perforations, and side screws passing through the bayonet slots and the fuse terminals into threaded engagement with the plates to clamp the fuse terminals between the plates and caps, said screws also passing into said perforations to secure the caps against endwise displacement on the tube.

ln testimony whereof, we hereunto affix our signatures.

LEON W. ROSENTHAL. GUSTLAVE d. LANG. 

